Montag, 12. Januar 2009

SSH login without password

You need an automatic login from host A / user a to Host B / user b. You don't want to enter any passwords, because you want to call ssh from a within a shell script.

First log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase:

a@A:~> ssh-keygen -t rsaGenerating public/private rsa key pair.Enter file in which to save the key (/home/a/.ssh/id_rsa): Created directory '/home/a/.ssh'.Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/a/.ssh/id_rsa.Your public key has been saved in /home/a/.ssh/id_rsa.pub.The key fingerprint is:3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A

Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine):

a@A:~> ssh b@B mkdir -p .sshb@B's password:

Finally append a's new public key to b@B:.ssh/authorized_keys and enter b's password one last time: